Internals: Columns: Renamed fields. Comments and tweak. Moved a demo block.

imgui.cpp

@@ -1140,7 +1140,7 @@ ImGuiStyle::ImGuiStyle()
     ItemInnerSpacing        = ImVec2(4,4);      // Horizontal and vertical spacing between within elements of a composed widget (e.g. a slider and its label)
     TouchExtraPadding       = ImVec2(0,0);      // Expand reactive bounding box for touch-based system where touch position is not accurate enough. Unfortunately we don't sort widgets so priority on overlap will always be given to the first widget. So don't grow this too much!
     IndentSpacing           = 21.0f;            // Horizontal spacing when e.g. entering a tree node. Generally == (FontSize + FramePadding.x*2).
-    ColumnsMinSpacing       = 6.0f;             // Minimum horizontal spacing between two columns
+    ColumnsMinSpacing       = 6.0f;             // Minimum horizontal spacing between two columns. Preferably > (FramePadding.x + 1).
     ScrollbarSize           = 16.0f;            // Width of the vertical scrollbar, Height of the horizontal scrollbar
     ScrollbarRounding       = 9.0f;             // Radius of grab corners rounding for scrollbar
     GrabMinSize             = 10.0f;            // Minimum width/height of a grab box for slider/scrollbar
@@ -5452,6 +5452,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         window->InnerClipRect.Min.y = ImFloor(0.5f + window->InnerMainRect.Min.y);
         window->InnerClipRect.Max.x = ImFloor(0.5f + window->InnerMainRect.Max.x - ImMax(0.0f, ImFloor(window->WindowPadding.x * 0.5f - window->WindowBorderSize)));
         window->InnerClipRect.Max.y = ImFloor(0.5f + window->InnerMainRect.Max.y);
+
         // Setup drawing context
         // (NB: That term "drawing context / DC" lost its meaning a long time ago. Initially was meant to hold transient data only. Nowadays difference between window-> and window->DC-> is dubious.)
         window->DC.Indent.x = 0.0f + window->WindowPadding.x - window->Scroll.x;
@@ -8434,12 +8435,12 @@ int ImGui::GetColumnsCount()
 
 static float OffsetNormToPixels(const ImGuiColumns* columns, float offset_norm)
 {
-    return offset_norm * (columns->MaxX - columns->MinX);
+    return offset_norm * (columns->OffMaxX - columns->OffMinX);
 }
 
 static float PixelsToOffsetNorm(const ImGuiColumns* columns, float offset)
 {
-    return offset / (columns->MaxX - columns->MinX);
+    return offset / (columns->OffMaxX - columns->OffMinX);
 }
 
 static const float COLUMNS_HIT_RECT_HALF_WIDTH = 4.0f;
@@ -8472,7 +8473,7 @@ float ImGui::GetColumnOffset(int column_index)
     IM_ASSERT(column_index < columns->Columns.Size);
 
     const float t = columns->Columns[column_index].OffsetNorm;
-    const float x_offset = ImLerp(columns->MinX, columns->MaxX, t);
+    const float x_offset = ImLerp(columns->OffMinX, columns->OffMaxX, t);
     return x_offset;
 }
 
@@ -8515,8 +8516,8 @@ void ImGui::SetColumnOffset(int column_index, float offset)
     const float width = preserve_width ? GetColumnWidthEx(columns, column_index, columns->IsBeingResized) : 0.0f;
 
     if (!(columns->Flags & ImGuiColumnsFlags_NoForceWithinWindow))
-        offset = ImMin(offset, columns->MaxX - g.Style.ColumnsMinSpacing * (columns->Count - column_index));
-    columns->Columns[column_index].OffsetNorm = PixelsToOffsetNorm(columns, offset - columns->MinX);
+        offset = ImMin(offset, columns->OffMaxX - g.Style.ColumnsMinSpacing * (columns->Count - column_index));
+    columns->Columns[column_index].OffsetNorm = PixelsToOffsetNorm(columns, offset - columns->OffMinX);
 
     if (preserve_width)
         SetColumnOffset(column_index + 1, offset + ImMax(g.Style.ColumnsMinSpacing, width));
@@ -8551,7 +8552,7 @@ void ImGui::PushColumnsBackground()
     ImGuiColumns* columns = window->DC.CurrentColumns;
     window->DrawList->ChannelsSetCurrent(0);
     int cmd_size = window->DrawList->CmdBuffer.Size;
-    PushClipRect(columns->BackupClipRect.Min, columns->BackupClipRect.Max, false); 
+    PushClipRect(columns->HostClipRect.Min, columns->HostClipRect.Max, false); 
     IM_ASSERT(cmd_size == window->DrawList->CmdBuffer.Size); // Being in channel 0 this should not have created an ImDrawCmd
 }
 
@@ -8597,9 +8598,8 @@ void ImGui::BeginColumns(const char* str_id, int columns_count, ImGuiColumnsFlag
     IM_ASSERT(columns_count >= 1);
     IM_ASSERT(window->DC.CurrentColumns == NULL); // Nested columns are currently not supported
 
-    ImGuiID id = GetColumnsID(str_id, columns_count);
-
     // Acquire storage for the columns set
+    ImGuiID id = GetColumnsID(str_id, columns_count);
     ImGuiColumns* columns = FindOrCreateColumns(window, id);
     IM_ASSERT(columns->ID == id);
     columns->Current = 0;
@@ -8609,11 +8609,11 @@ void ImGui::BeginColumns(const char* str_id, int columns_count, ImGuiColumnsFlag
 
     // Set state for first column
     const float content_region_width = (window->SizeContentsExplicit.x != 0.0f) ? (window->SizeContentsExplicit.x) : (window->InnerClipRect.Max.x - window->Pos.x);
-    columns->MinX = window->DC.Indent.x - g.Style.ItemSpacing.x; // Lock our horizontal range
-    columns->MaxX = ImMax(content_region_width - window->Scroll.x, columns->MinX + 1.0f);
-    columns->BackupCursorPosY = window->DC.CursorPos.y;
-    columns->BackupCursorMaxPosX = window->DC.CursorMaxPos.x;
-    columns->BackupClipRect = window->ClipRect;
+    columns->OffMinX = window->DC.Indent.x - g.Style.ItemSpacing.x; // Lock our horizontal range
+    columns->OffMaxX = ImMax(content_region_width - window->Scroll.x, columns->OffMinX + 1.0f);
+    columns->HostCursorPosY = window->DC.CursorPos.y;
+    columns->HostCursorMaxPosX = window->DC.CursorMaxPos.x;
+    columns->HostClipRect = window->ClipRect;
     columns->LineMinY = columns->LineMaxY = window->DC.CursorPos.y;
     window->DC.ColumnsOffset.x = 0.0f;
     window->DC.CursorPos.x = (float)(int)(window->Pos.x + window->DC.Indent.x + window->DC.ColumnsOffset.x);
@@ -8622,7 +8622,7 @@ void ImGui::BeginColumns(const char* str_id, int columns_count, ImGuiColumnsFlag
     if (columns->Columns.Size != 0 && columns->Columns.Size != columns_count + 1)
         columns->Columns.resize(0);
 
-    // Initialize defaults
+    // Initialize default widths
     columns->IsFirstFrame = (columns->Columns.Size == 0);
     if (columns->Columns.Size == 0)
     {
@@ -8668,17 +8668,19 @@ void ImGui::EndColumns()
         window->DrawList->ChannelsMerge();
     }
 
+    const ImGuiColumnsFlags flags = columns->Flags;
     columns->LineMaxY = ImMax(columns->LineMaxY, window->DC.CursorPos.y);
     window->DC.CursorPos.y = columns->LineMaxY;
-    if (!(columns->Flags & ImGuiColumnsFlags_GrowParentContentsSize))
-        window->DC.CursorMaxPos.x = columns->BackupCursorMaxPosX;  // Restore cursor max pos, as columns don't grow parent
+    if (!(flags & ImGuiColumnsFlags_GrowParentContentsSize))
+        window->DC.CursorMaxPos.x = columns->HostCursorMaxPosX;  // Restore cursor max pos, as columns don't grow parent
 
     // Draw columns borders and handle resize
+    // The IsBeingResized flag ensure we preserve pre-resize columns width so back-and-forth are not lossy
     bool is_being_resized = false;
-    if (!(columns->Flags & ImGuiColumnsFlags_NoBorder) && !window->SkipItems)
+    if (!(flags & ImGuiColumnsFlags_NoBorder) && !window->SkipItems)
     {
         // We clip Y boundaries CPU side because very long triangles are mishandled by some GPU drivers.
-        const float y1 = ImMax(columns->BackupCursorPosY, window->ClipRect.Min.y);
+        const float y1 = ImMax(columns->HostCursorPosY, window->ClipRect.Min.y);
         const float y2 = ImMin(window->DC.CursorPos.y, window->ClipRect.Max.y);
         int dragging_column = -1;
         for (int n = 1; n < columns->Count; n++)
@@ -8693,7 +8695,7 @@ void ImGui::EndColumns()
                 continue;
 
             bool hovered = false, held = false;
-            if (!(columns->Flags & ImGuiColumnsFlags_NoResize))
+            if (!(flags & ImGuiColumnsFlags_NoResize))
             {
                 ButtonBehavior(column_hit_rect, column_id, &hovered, &held);
                 if (hovered || held)
@@ -8745,6 +8747,7 @@ void ImGui::Columns(int columns_count, const char* id, bool border)
         BeginColumns(id, columns_count, flags);
 }
 
+
 //-----------------------------------------------------------------------------
 // [SECTION] DRAG AND DROP
 //-----------------------------------------------------------------------------
@@ -9692,7 +9695,7 @@ void ImGui::ShowMetricsWindow(bool* p_open)
         {
             if (!ImGui::TreeNode((void*)(uintptr_t)columns->ID, "Columns Id: 0x%08X, Count: %d, Flags: 0x%04X", columns->ID, columns->Count, columns->Flags))
                 return;
-            ImGui::BulletText("Width: %.1f (MinX: %.1f, MaxX: %.1f)", columns->MaxX - columns->MinX, columns->MinX, columns->MaxX);
+            ImGui::BulletText("Width: %.1f (MinX: %.1f, MaxX: %.1f)", columns->OffMaxX - columns->OffMinX, columns->OffMinX, columns->OffMaxX);
             for (int column_n = 0; column_n < columns->Columns.Size; column_n++)
                 ImGui::BulletText("Column %02d: OffsetNorm %.3f (= %.1f px)", column_n, columns->Columns[column_n].OffsetNorm, OffsetNormToPixels(columns, columns->Columns[column_n].OffsetNorm));
             ImGui::TreePop();

imgui.h

@@ -1293,7 +1293,7 @@ struct ImGuiStyle
     ImVec2      ItemInnerSpacing;           // Horizontal and vertical spacing between within elements of a composed widget (e.g. a slider and its label).
     ImVec2      TouchExtraPadding;          // Expand reactive bounding box for touch-based system where touch position is not accurate enough. Unfortunately we don't sort widgets so priority on overlap will always be given to the first widget. So don't grow this too much!
     float       IndentSpacing;              // Horizontal indentation when e.g. entering a tree node. Generally == (FontSize + FramePadding.x*2).
-    float       ColumnsMinSpacing;          // Minimum horizontal spacing between two columns.
+    float       ColumnsMinSpacing;          // Minimum horizontal spacing between two columns. Preferably > (FramePadding.x + 1).
     float       ScrollbarSize;              // Width of the vertical scrollbar, Height of the horizontal scrollbar.
     float       ScrollbarRounding;          // Radius of grab corners for scrollbar.
     float       GrabMinSize;                // Minimum width/height of a grab box for slider/scrollbar.

imgui_demo.cpp

@@ -2426,6 +2426,32 @@ static void ShowDemoWindowColumns()
         ImGui::TreePop();
     }
 
+    if (ImGui::TreeNode("Borders"))
+    {
+        // NB: Future columns API should allow automatic horizontal borders.
+        static bool h_borders = true;
+        static bool v_borders = true;
+        ImGui::Checkbox("horizontal", &h_borders);
+        ImGui::SameLine();
+        ImGui::Checkbox("vertical", &v_borders);
+        ImGui::Columns(4, NULL, v_borders);
+        for (int i = 0; i < 4 * 3; i++)
+        {
+            if (h_borders && ImGui::GetColumnIndex() == 0)
+                ImGui::Separator();
+            ImGui::Text("%c%c%c", 'a' + i, 'a' + i, 'a' + i);
+            ImGui::Text("Width %.2f", ImGui::GetColumnWidth());
+            ImGui::Text("Offset %.2f", ImGui::GetColumnOffset());
+            ImGui::Text("Long text that is likely to clip");
+            ImGui::Button("Button", ImVec2(-1.0f, 0.0f));
+            ImGui::NextColumn();
+        }
+        ImGui::Columns(1);
+        if (h_borders)
+            ImGui::Separator();
+        ImGui::TreePop();
+    }
+
     // Create multiple items in a same cell before switching to next column
     if (ImGui::TreeNode("Mixed items"))
     {
@@ -2472,32 +2498,6 @@ static void ShowDemoWindowColumns()
         ImGui::TreePop();
     }
 
-    if (ImGui::TreeNode("Borders"))
-    {
-        // NB: Future columns API should allow automatic horizontal borders.
-        static bool h_borders = true;
-        static bool v_borders = true;
-        ImGui::Checkbox("horizontal", &h_borders);
-        ImGui::SameLine();
-        ImGui::Checkbox("vertical", &v_borders);
-        ImGui::Columns(4, NULL, v_borders);
-        for (int i = 0; i < 4*3; i++)
-        {
-            if (h_borders && ImGui::GetColumnIndex() == 0)
-                ImGui::Separator();
-            ImGui::Text("%c%c%c", 'a'+i, 'a'+i, 'a'+i);
-            ImGui::Text("Width %.2f", ImGui::GetColumnWidth());
-            ImGui::Text("Offset %.2f", ImGui::GetColumnOffset());
-            ImGui::Text("Long text that is likely to clip");
-            ImGui::Button("Button", ImVec2(-1.0f, 0.0f));
-            ImGui::NextColumn();
-        }
-        ImGui::Columns(1);
-        if (h_borders)
-            ImGui::Separator();
-        ImGui::TreePop();
-    }
-
     // Scrolling columns
     /*
     if (ImGui::TreeNode("Vertical Scrolling"))

imgui_internal.h

@@ -680,11 +680,11 @@ struct ImGuiColumns
     bool                IsBeingResized;
     int                 Current;
     int                 Count;
-    float               MinX, MaxX;
+    float               OffMinX, OffMaxX;       // Offsets from HostWorkRect.Min.x
     float               LineMinY, LineMaxY;
-    float               BackupCursorPosY;       // Backup of CursorPos at the time of BeginColumns()
-    float               BackupCursorMaxPosX;    // Backup of CursorMaxPos at the time of BeginColumns()
-    ImRect              BackupClipRect;
+    float               HostCursorPosY;         // Backup of CursorPos at the time of BeginColumns()
+    float               HostCursorMaxPosX;      // Backup of CursorMaxPos at the time of BeginColumns()
+    ImRect              HostClipRect;           // Backup of ClipRect at the time of BeginColumns()
     ImVector<ImGuiColumnData> Columns;
 
     ImGuiColumns()      { Clear(); }
@@ -696,10 +696,10 @@ struct ImGuiColumns
         IsBeingResized = false;
         Current = 0;
         Count = 1;
-        MinX = MaxX = 0.0f;
+        OffMinX = OffMaxX = 0.0f;
         LineMinY = LineMaxY = 0.0f;
-        BackupCursorPosY = 0.0f;
-        BackupCursorMaxPosX = 0.0f;
+        HostCursorPosY = 0.0f;
+        HostCursorMaxPosX = 0.0f;
         Columns.clear();
     }
 };